Find the bottlenecks in your backup process
In this post we’ll make a quick trip through LiteSpeed’s Backup Analyzer, and then focus on several key metrics it outputs. These metrics will show you which part of your backup process is slowing things down.
To start, right-click the database in question and choose Backup Analyzer:
This will launch the Backup Analyzer wizard:
Some quick notes on the selections you can make in the wizard:
- Backup Location – use your normal backup location to get relevant results. Remember that you can stripe by adding multiple files
- Data Sample – if your database has just character and numeric data in, you can get good results with a small sample (say, 10 or 20%)
- Compression Level – testing the odd levels only should suffice to give you the general trend
- Encryption Options – here you can see the additional cost of encrypting your backups
- Analyzer Schedule – don’t choose “Run Immediately” – it keeps the wizard open until the test finishes!
When your test has run, you can view the results in the Backup Analyzer tab, choosing the results for various tests from the Existing Test dropdown.
The main point of the Backup Analyzer is to show you the time required to achieve each level of compression, but our focus here is on three key metrics: Read Speed, Throughput and Backup Speed. To understand these numbers, think of a backup as a three-step process. First the live database needs to be streamed from its drive into memory. Second, as this data arrives in memory, LiteSpeed needs to compress the data. And third, the compressed data must be written to the backup file on the target drive.
The speed of these three steps is recorded as Read Speed, Throughput and Backup Speed. If your lowest number is Read Speed, then the speed of your live database drive is your bottleneck. If your lowest number is Throughput, then compressing the data (and thus CPU power) is your limitation. If your lowest number is Backup Speed, then the target drive where the backup is being written to is the weak link in the chain.
With this information, you can upgrade the appropriate resource to improve your backup performance!
All of my Quest Database Performance blog posts can be found here.